Hydroforming apparatus

ABSTRACT

The present invention provides a Hydroforming apparatus comprising of a cylindrical shaped upper and lower die holders and a cylindrical shaped outer ring with upper and lower cam segments and tapered wedges that is powered by hydraulic cylinders or any other means such that the tapered wedges are used to exert force on the lower cam segments such that the upper and lower cam holders are kept closed during the hydroforming operation. And because the cylindrical shape is efficient in carrying loads, the size of the new hydroforming apparatus is smaller than conventional hydroforming apparatus. The cylindrical shaped outer ring is made of two or more rings inserted inside each other such that the outer ring is exerting pressure on the inner ring such that no deformation occurs in the outer ring during the hydroforming operation such that the energy used to keep the hydroforming die closed during the hydroforming operation is kept to a minimum. The upper and lower cam segments and the tapered wedges are replaced with a diaphragm filled with hydraulic fluid and hydraulic pressure is added to keep the die closed during the hydroforming operation.

This application Claims the benefits of prior filing date of provisional application No. US60/715,581—Filing date Sep. 12, 2005—Applicant Mohamed T. Gharib, Brantford, Canada

BACKGROUND AND SUMMARY OF THE INVENTION

Many parts such as the ones used in automotive structures are manufactured using a hydroforming process. The hydroforming process requires large presses up to 5,000 tons to hold the hydroforming die close during the hydroforming process. These presses are large, expensive, require large amount of energy to operate and requires special and expensive installations, yet the work is done using the hydroforming pressure not the press forces. In an effort to reduce the automotive vehicle weight, high strength steel is being used, which means larger hydroforming presses, are required.

This invention relates to an apparatus where the hydroforming die holder has an outer cylindrical shape and a cylindrical ring containing tapered wedges and upper and lower cams, which are fitted over the cylindrical shape of the die holder. The said tapered wedges are extended using hydraulic cylinders such that the said lower cam segments are clamping over the said die holder and keeping the said die close. The forces required to close the said die are transmitted to the said outer cylindrical shape. And hence the said outer cylindrical shapes can carry large loads, the size, weight and cost of the apparatus is kept to a minimum.

Furthermore the said outer cylinder is made of two or more rings and presses together such that the inner ring is in compression such that the said inner ring will not expand as the hydroforming pressure is applied.

Furthermore, the said tapered wedges can be replaced by a cylindrical diaphragm or other means that are obvious to one who is skilled in the art. Pressure is applied inside the said diaphragm in order to keep the said die close.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings wherein:

FIG. 1 is a sectional view of a hydroforming apparatus according to current invention showing the outer ring over the die holder.

FIGS. 2 a and 2 b is a sectional view of a hydroforming apparatus according to prior art showing the hydroforming die in an open and closed positions.

FIG. 3 is a hydroforming apparatus according to prior art showing the hydroforming die in a hydroforming press.

FIG. 4 is a sectional view of a Hydroforming apparatus according to current invention without the outer ring showing the hydroforming die in the open position

FIG. 5 is a sectional view of a Hydroforming apparatus according to current invention without the outer ring showing the hydroforming die in the closed position

FIG. 6 is sectional views of the outer ring with the tapered wedges are in the retracted position and the lower cam segments are in the open position.

FIG. 6 a is showing details of the tapered wedge and the lower cam segments.

FIG. 7 is sectional views of the outer ring with the tapered wedges are in the extended position and the lower cam segments are in the closed position.

FIG. 8 is a cross sectional view of the outer ring showing cross sectional details of the tapered wedge, the lower cam segments and the upper cam segments.

FIG. 9 is a sectional view of the outer ring showing guide rods and bushings.

FIG. 10 is a sectional view of the die and die holder and outer ring with the die closed and the outer ring are in the returned position.

FIG. 11 is a sectional view showing the outer ring in the forward position and over the die holder and in the hydroforming position.

FIG. 12 is a sectional view showing the outer ring in the returned position and the die holder in the open position after hydroforming is complete.

FIG. 13 is showing the outer ring made of two rings and is pre-stressed to reduce deformation.

FIG. 14. Showing the tapered wedge made of one ring with one cylinder

FIG. 15 is showing the outer ring is made of two sets of tapered wedges and cylinders and upper and lower cams. One set is located on each side.

FIG. 16 is a sectional view of a hydroforming apparatus according to this invention with two outer rings. One outer ring is located on each side of the die holder.

FIG. 17 is a sectional view of a hydroforming apparatus according to this invention with a diaphragm filled with hydraulic pressure is used to keep the die closed.

FIG. 18 is showing a double tapered wedge and lower cam segment

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Processes such as Hydroforming process requires large presses to clamp the die in place while forming (work) is being done by other means such as applying internal pressure to form the part.

With reference to FIGS. 2 a and 2 b, a description of the prior art hydroforming technique for forming round tubes into multi lateral or irregular shapes will be described. The hydroforming technique according to the prior art includes providing a die 10 including a lower portion 12 and an upper portion 14 which combine to define a die cavity 16. The upper portion 14 is moved generally downward into a closed position forming a die cavity 16 over a round tube 22. Side plugs 18 and 20 are moved sideway to seal both ends of tube 22 and hydraulic pressure source is connected to the interior of tube 22 through an opening 24 inside plugs 18 and 20 and thereby expanding tube 22 so as to conform to the shape of the die cavity 16.

The force F required to keep the said die 10 closed varies according to the size of the said tube 22 and is in the magnitude of thousands of tons. In order to supply the said force F large press is used to keep the said die 10 closed. This said press have a force F of 5,000 tons or more. With reference to FIG. 3, the said press is large and expensive. The said press base is often mounted under the ground, which requires expensive installation

Current Invention

With reference to FIGS. 4 and 5, the hydroforming technique according to the current invention includes providing a die 10 including a lower die section 12 and an upper die section 14 which combine to define a die cavity 16. The said lower die section 12 is mounted in a lower die holder 26 and the said upper die section 14 is mounted in an upper die holder 28. The said lower die 12 and the said lower die holder 26 are fixed and the said upper die 14 and the said upper die holder 28 are allowed to move up and down between an open position as shown in FIG. 4 and a closed position as shown in FIG. 5.

The said upper die holder 28 is guided with the said lower die holder 26 by using guide rods 24 and guide bushings 30 or by any other means that are obvious to those who are skilled in the art. Furthermore, the said upper die holder 28 is moved up and down using hydraulic cylinder 32 mounted to frame 34 or by any other means that is obvious to those who are skilled in the art.

Furthermore the outer surface 27 of the said lower die holder 26 is shaped as half cylindrical shape and the outer surface 29 of the said upper die holder 28 is shaped as half cylindrical shape such that when the said upper die holder 28 is moved to the closed position, the said outer surface 27 of the said lower die holder 26 and the said outer surface 29 of the said upper die holder 28 combine to form a cylindrical shape.

With reference to FIGS. 6, 6 a, 7 and 8, the current invention includes providing an outer ring 36 including a ring 38 and upper cam segment 40 and tapered wedge 42 and lower cam segment 44. The said upper cam segment 40 is attached to the inner surface 39 of the said ring 38 and the said lower cam segment 44 is attached to the said ring 38 using bolts 58 and springs 60 such that the said lower cam segment 44 is allowed to travel in the direction of arrow R between an open and a close position. The said tapered wedge 42 is placed between the said upper cam segment 40 and the said lower cam segment 44 and is powered by a cylinder 48 such that the said tapered wedge 42 is allowed to move in the direction of arrow X between a retracted and extended positions. The said cylinder 48 is attached to the said ring 38 using mounting bracket 50. In addition, the lower surface 52 of the said tapered wedge 42 is tapered with a small angle 53 that is smaller than 45 degrees and the upper surface 54 of the said lower cam segment 44 is tapered with a small angle 55 that is the same as the said small angle 53 on the said lower surface 52 of the said tapered wedge 42 as illustrated in FIG. 6 a such that when the said taper wedge 42 is in the said retracted position, the said lower cam segment 40 is moved by the said springs 60 to the said open position as shown in FIG. 6 and as the said tapered wedge 42 is moved to the said extended position, the said lower cam segment 40 is moved to the said closed position as shown in FIG. 7. The said cylinder 48 will exert force F1 on the said tapered wedge 42. The said tapered surface 52 of the said tapered wedge 42 is in contact with the said tapered surface 54 of the said lower cam segment 44 such that the said force F1 that is exerted on the said tapered wedge 42 is transmitted to a force F2 that is exerted on the said lower cam segment 44 in a direction perpendicular to the said force F1. And since the said small angles 53 and 55 are smaller than 45 degrees, then the said force F2 is greater than the said force F1. In practice and according to this invention, the said angles 53 and 54 will have a slope of a ratio 5:1 to 20:1 such that the said force F2 is greater than the said force F1 by a ratio 5 times to 20 times respectively.

With reference to FIG. 8, the lower surface 56 of the said lower cam segment 44 is curved with the same cylindrical radius as the said outer surfaces 27 and 29 of the said lower die holder 26 and the said upper die holder 28.

With reference to FIG. 8 the said upper cam segment 40 and the said taper wedge 42 and the said lower cam segment 44 and the said cylinder 48 will be equal in number and can be of one or more. FIG. 8 shows 24 of the said upper cam segments 40 and the said taper wedges 42 and the said lower cam segments 44 and the said cylinders 48.

With Reference to FIG. 9, the said outer ring 36 is guided by guide rods 62 and guide bushings 64 such that the said outer ring 36 can be moved horizontally between a forward and returned position. The said movement of the said outer ring 36 can be by a cylinder or a motor and gear and rack or any other mean that is obvious to those who are skilled in the art. The means of guiding the said outer ring 36 can be as described using the said guide rods 62 and the said guide bushings 64 or by other means that are obvious to those who are skilled in the art.

In operation and according to this invention and with reference to FIGS. 10, 11 and 12 the said upper die holder 28 and the said upper die section 14 are moved to the said open position. The said tube 22 is placed in the said cavity 16 of the said lower die section 12. The said upper die holder 28 and the said upper die section 14 are moved downward into the said closed position forming the said die cavity 16 over the said tube 22. The said side plugs 18 and 20 are moved sideway to seal both ends of the said tube 22. The said outer ring 36 is in the said return position and the said tapered wedges 42 are moved to the said retracted position allowing the said lower cam segments 44 to move to the said open position. The said outer ring 36 is moved horizontally to the said forward position such that the said lower die holder 26 and the said upper die holder 28 are contained inside the lower cam segments 44 as illustrated in FIG. 11. The said cylinders 48 are extended moving the said tapered wedges 42 to the said extended position and the said lower cam segments 44 to the said closed position. The said curved lower surface 56 of the said lower cam segments 44 will come into contact with the said curved outer surface 27 of the said lower die holder 26 and the said curved outer surface 29 of the said upper die holder 28. The said cylinders 48 will exert the said force F1 on the said tapered wedges 42 and the said tapered wedges 42 will exert the said force F2 on the said lower cam segments 44. Since the said lower cam segments 44 are in contact with the said lower die holder 26 and the said upper die holder 28, the said Force F2 is transmitted to the said lower and upper die holders 26 and 28. The said force F2 will keep the said Lower and upper die holders 26 and 28 closed and keep the said lower die section 12 and the said upper die section 14 closed during the hydroforming operation.

A hydraulic pressure source is now connected to the interior of the said tube 22 through the said opening 24 inside the said plugs 18 and 20 and thereby expanding the said tube 22 so as to conform to the said shape of the said die cavity 16. The said hydraulic pressure will be disconnected and the said cylinders 48 will retract moving the said tapered wedges 42 to the said retracted position and the said lower cam segments 44 to the said open position. This will allow the said outer ring 36 to move horizontally to the said returned position and the said upper die holder 28 and the said upper die segment 14 to move to the said open position allowing the removal of the said tube 22 as illustrated in FIG. 12.

Since the said force F2 is greater than the said force F1, then the force require the keep the said die 10 closed during the hydroforming operation is smaller.

And since the force F2 required to keep the said die 10 closed is contained within the said ring 38 and since the said ring 38 is of a cylindrical shape, and since cylindrical shapes are efficient in load carrying, the structure for the apparatus as per this invention is smaller and lighter that prior art.

In practice and according to this invention the said bolts 58 and the said springs 60 are replaced by a double tapered wedge 78 instead off the tapered wedge 42 and double tapered lower cam segment 82 instead of the lower cam segment 44 as shown in FIG. 18 or any other mans that is obvious to one who is skilled in the art, such that the second taper 80 is used to move the said lower cam segments 82 to the said open position.

In practice and according to this invention, the said ring 38 is made of two or more rings 68 and 70 as illustrated in FIG. 13. The said outer ring 68 is pressed over the said inner ring 70 such that the said outer ring 68 is exerting pressure F3 over the outer surface of the said inner ring 70 such that the said outer ring 68 is under tension forces F4 while the said inner ring 70 is under compression forces F5 and the amount of the said pressure F3 is such that the said compression force F5 in the said inner ring 70 is greater than the said force F2 required to keep the said die 10 closed during the hydroforming operation such that no expansion in the said ring 36 will occur as a result of the hydroforming operation and such that the energy required to keep the said die 10 closed during the hydroforming operation is kept to a minimum.

In practice and according to this invention the said tapered wedges 42 is made of one tapered ring 43 and moved by one cylinder 74. In such a case the said tapered lower surface 52 of the said tapered ring 43 is cylindrical in shape and the said upper tapered surface 54 of the said lower cam segments 44 is also cylindrical to match the said tapered and cylindrical surface 52. Similarly the outer surface 72 of the said tapered ring 43 is cylindrical and matches the said inner surface 39 of the said outer cam segments 40.

In practice and according to this invention the said outer ring 36 will provide the said tapered wedges 42 and the said upper cam segments 40 and the said lower cam segments 44 and the said cylinders 48 and the said brackets 50 from both sides as illustrated in FIG. 15.

In practice and according to this invention providing two of the said outer rings 36 one from either side of the said upper and lower die holders 26 and 28 as illustrated in FIG. 16 such that the travel of the said outer ring 36 between the said forward and return position is kept to a minimum.

In practice and according to this invention the said tapered wedges and the said cylinders and the said upper and lower cam segments are replaced by a diaphragm 76. The said diaphragm 76 is filled with hydraulic fluid and hydraulic pressure is added inside the said diaphragm 76 such that the said diaphragm 76 will exert force on the said upper and lower die holders 26 and 28 such that the said die 10 is kept in the said closed position during the said hydroforming operation

The movement of the said outer ring horizontally between the said open and closed positions can be vertically between an upper and lower position and the said die holders 28 and 26 and the said die 10 are mounted vertically.

The Invention describes a fixed said lower die holder 26 and said lower die 12 and a movable said die upper holder 28 and said upper die 14. Both Said Upper and Lower Die Holders 26 and 28 and said Upper and Lower dies 12 and 14 can be movable or the said Upper die holder 28 and the said upper die 14 are fixed while the said lower die holder 26 and the said lower die 12 are movable.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of this invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

1. A Hydroforming apparatus providing an upper die holder containing the upper section of hydroforming die and providing a lower die holder containing the lower section of the said hydroforming die. The Said lower die holder and the said lower die section are fixed while the said upper die holder and the said upper die section are allowed to move between an open and a closed positions. And providing the outer surface of the said upper die holder is shaped as half cylindrical shape and the outer surface of the said lower die holder is also shaped as half cylindrical shape such that when the said upper die holder is moved to the said closed position, the said outer surface of the said lower die holder and the said outer surface of the said upper die holder combine to form a cylindrical shape. And providing an outer ring including a ring and upper cam segment and lower cam segment and providing the said upper cam segment is attached to the inner surface of the said ring and the said lower cam segment is attached to the said ring with bolts and springs or double taper or any other means that is obvious to one who is skilled in the art such that the said lower cam segment is allowed to travel in the radial direction between an open and a close position. And providing a tapered wedge that is placed between the said upper cam segment and the said lower cam segment and is powered with a hydraulic cylinder or by any other means that are obvious to one who is skilled in the art such that the said tapered wedge is allowed to move in the horizontal direction between a retracted and extended positions. And providing the lower surface of the said tapered wedge is tapered with a small angle that is smaller than 45 degrees and the upper surface of the said lower cam segment is tapered with the same said small angle on the said lower surface of the said tapered wedge such that when the said taper wedge is in the said retracted position, the said lower cam segment is moved to the said open position and such that as the said tapered wedge is moved to the said extended position and the said lower cam segment is moved to the said closed position and such that the said cylinder or other power source will exert a force F1 on the said tapered wedge and such that the said tapered surface of the said tapered wedge is in contact with the said tapered surface of the said lower cam segment such that the said force F1 that is exerted on the said tapered wedge is transmitted to a force F2 that is exerted on the said lower cam segment in a direction perpendicular to the said force F1. And providing the lower surface of the said lower cam segment is curved with the same cylindrical radius as the said outer surfaces of the said lower die holder and the said upper die holder. And providing the said upper cam segment and the said taper wedge and the said lower cam segment and the said cylinder or other power source are equal in number and is more than one. And providing the said outer ring along with the said ring and the said upper cam segments and the said lower cam segments and the said tapered wedges and the said hydraulic cylinders are moved horizontally between a forward and return position. And where the said upper die holder and the said upper die section are moved to the said open position and a tube is placed in the cavity of the said lower die section and the said upper die holder and the said upper die section are moved downward into the said closed position and the said tube is sealed on both ends and the said outer ring is in the said return position and the said tapered wedges are in the said retracted position and the said lower cam segments are in the said open position. And where the said outer ring along with the said ring and the said upper cam segments and the said lower cam segments and the said tapered wedges and the said hydraulic cylinders or the said other power source are moved horizontally to the said forward position such that the said lower die holder and the said upper die holder are contained inside the lower cam segments and where the said cylinders or the said other power source are extended moving the said tapered wedges to the said extended position and the said lower cam segments to the said closed position and where the said curved lower surface of the said lower cam segments will come into contact with the said curved outer surface of the said lower die holder and the said curved outer surface of the said upper die holder and where the said cylinders or the said other power source will exert the said force F1 on the said tapered wedges and the said tapered wedges will exert the said force F2 on the said lower cam segments and where the said Force F2 is transmitted to the said Lower and upper die holders such that the said force F2 will keep the said Lower and upper die holders and the said lower and upper die section closed during the hydroforming operation. And where a hydraulic pressure source is connected to the interior of the said tube and thereby expanding the said tube so as to conform to the said shape of the said die cavity and where the said hydraulic pressure is disconnected and the said cylinders or the said other power source are retracted moving the said tapered wedges to the said retracted position and the said lower cam segments to the said open position allowing the said outer ring to move horizontally to the said returned position and the said upper die holder and the said upper die segment to move to the said open position allowing the removal of the said tube. And where the said force F2 required to keep the said die closed is contained within the said ring such that the structure for the apparatus as per this invention is smaller and lighter that prior art and such that the force required to keep the said die closed during the said hydroforming operation is kept to a minimum.
 2. A Hydroforming apparatus according to claim 1 where the said ring is made of two or more rings and where the said outer ring or rings are pressed over the said inner ring such that the said outer ring or rings are exerting pressure over the outer surface of the said inner ring such that the said outer ring or rings are under tension forces while the said inner ring is under compression forces and the amount of the said pressure exerted by outer ring or rings is such that the said compression force in the said inner ring is greater than the force required to keep the said die closed during the hydroforming operation such that no expansion in the said ring will occur as a result of the hydroforming operation and such that the energy required to keep the said die closed during the hydroforming operation is kept to a minimum.
 3. A Hydroforming apparatus according to claim 1 where the said tapered wedges are made of one tapered ring and moved by one cylinder and providing a tapered lower surface of the said tapered ring is cylindrical in shape and the said upper tapered surface of the said lower cam segments are also cylindrical to match the said tapered and cylindrical surface and providing the outer surface of the said tapered ring is cylindrical and matches the said inner surface of the said outer cam segments.
 4. A Hydroforming apparatus according to claim 1 where the said outer ring provides the said tapered wedges and the said upper cam segments and the said lower cam segments and the said cylinders from both sides such that the length of the said tapered wedges and the said upper cam segments and the said lower cam segments is reduced to a practical length.
 5. A Hydroforming apparatus according to claim 1 providing two of the said outer rings one from either side of the said upper and lower die holders such that the travel of the said outer ring between the said forward and return position is kept to a minimum.
 6. A Hydroforming apparatus according to claim 1 where the said bolts and the said springs are replaced by a double tapered wedge and a double taper lower cam segments, such that the second taper is used to move the said lower cam segments to the said open position.
 7. A Hydroforming apparatus according to claim 1 where the said tapered wedges and the said cylinders and the said upper and lower cam segments are replaced by a diaphragm and where the said diaphragm is filled with hydraulic fluid and hydraulic pressure is added inside the said diaphragm such that the said diaphragm will exert force on the said upper and lower die holders such that the said die is kept in the said closed position during the said hydroforming operation.
 8. A Hydroforming apparatus according to claim 1 through 7 where both said Upper and Lower Die Holders and said Upper and Lower dies are movable
 9. A Hydroforming apparatus according to claim 1 through 7 where the said upper die holder and said upper die are fixed and the said lower die holder and the said lower die are movable.
 10. A Hydroforming apparatus according to claims 1 through 9 where the apparatus is mounted vertically such that the movement of the said outer ring between the said open and closed positions is vertical between an upper and lower position and the said die holders and the said dies are mounted vertically. 